<?php

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	exit ( 'No direct script access allowed' );
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------


/**
 * Session Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Sessions
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/sessions.html
 */
class CI_Session {
	
	var $sess_encrypt_cookie = FALSE;
	var $sess_use_database = FALSE;
	var $sess_table_name = '';
	var $sess_expiration = 7200;
	var $sess_expire_on_close = FALSE;
	var $sess_match_ip = FALSE;
	var $sess_match_useragent = TRUE;
	var $sess_cookie_name = 'ci_session';
	var $cookie_prefix = '';
	var $cookie_path = '';
	var $cookie_domain = '';
	var $cookie_secure = FALSE;
	var $sess_time_to_update = 300;
	var $encryption_key = '';
	var $flashdata_key = 'flash';
	var $time_reference = 'time';
	var $gc_probability = 5;
	var $userdata = array ();
	var $CI;
	var $now;
	
	/**
	 * Session Constructor
	 *
	 * The constructor runs the session routines automatically
	 * whenever the class is instantiated.
	 */
	public function __construct($params = array()) {
		log_message ( 'debug', "Session Class Initialized" );
		
		// Set the super object to a local variable for use throughout the class
		$this->CI = & get_instance ();
		
		// Set all the session preferences, which can either be set
		// manually via the $params array above or via the config file
		foreach ( array ('sess_encrypt_cookie', 'sess_use_database', 'sess_table_name', 'sess_expiration', 'sess_expire_on_close', 'sess_match_ip', 'sess_match_useragent', 'sess_cookie_name', 'cookie_path', 'cookie_domain', 'cookie_secure', 'sess_time_to_update', 'time_reference', 'cookie_prefix', 'encryption_key' ) as $key ) {
			$this->$key = (isset ( $params [$key] )) ? $params [$key] : $this->CI->config->item ( $key );
		}
		
		if ($this->encryption_key == '') {
			show_error ( 'In order to use the Session class you are required to set an encryption key in your config file.' );
		}
		
		// Load the string helper so we can use the strip_slashes() function
		$this->CI->load->helper ( 'string' );
		
		// Do we need encryption? If so, load the encryption class
		if ($this->sess_encrypt_cookie == TRUE) {
			$this->CI->load->library ( 'encrypt' );
		}
		
		// Are we using a database?  If so, load it
		if ($this->sess_use_database === TRUE and $this->sess_table_name != '') {
			$this->CI->load->database ();
		}
		
		// Set the "now" time.  Can either be GMT or server time, based on the
		// config prefs.  We use this to set the "last activity" time
		$this->now = $this->_get_time ();
		
		// Set the session length. If the session expiration is
		// set to zero we'll set the expiration two years from now.
		if ($this->sess_expiration == 0) {
			$this->sess_expiration = (60 * 60 * 24 * 365 * 2);
		}
		
		// Set the cookie name
		$this->sess_cookie_name = $this->cookie_prefix . $this->sess_cookie_name;
		
		// Run the Session routine. If a session doesn't exist we'll
		// create a new one.  If it does, we'll update it.
		if (! $this->sess_read ()) {
			$this->sess_create ();
		} else {
			$this->sess_update ();
		}
		
		// Delete 'old' flashdata (from last request)
		$this->_flashdata_sweep ();
		
		// Mark all new flashdata as old (data will be deleted before next request)
		$this->_flashdata_mark ();
		
		// Delete expired sessions if necessary
		$this->_sess_gc ();
		
		log_message ( 'debug', "Session routines successfully run" );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Fetch the current session data if it exists
	 *
	 * @access	public
	 * @return	bool
	 */
	function sess_read() {
		// Fetch the cookie
		$session = $this->CI->input->cookie ( $this->sess_cookie_name );
		
		// No cookie?  Goodbye cruel world!...
		if ($session === FALSE) {
			log_message ( 'debug', 'A session cookie was not found.' );
			return FALSE;
		}
		
		// Decrypt the cookie data
		if ($this->sess_encrypt_cookie == TRUE) {
			$session = $this->CI->encrypt->decode ( $session );
		} else {
			// encryption was not used, so we need to check the md5 hash
			$hash = substr ( $session, strlen ( $session ) - 32 ); // get last 32 chars
			$session = substr ( $session, 0, strlen ( $session ) - 32 );
			
			// Does the md5 hash match?  This is to prevent manipulation of session data in userspace
			if ($hash !== md5 ( $session . $this->encryption_key )) {
				log_message ( 'error', 'The session cookie data did not match what was expected. This could be a possible hacking attempt.' );
				$this->sess_destroy ();
				return FALSE;
			}
		}
		
		// Unserialize the session array
		$session = $this->_unserialize ( $session );
		
		// Is the session data we unserialized an array with the correct format?
		if (! is_array ( $session ) or ! isset ( $session ['session_id'] ) or ! isset ( $session ['ip_address'] ) or ! isset ( $session ['user_agent'] ) or ! isset ( $session ['last_activity'] )) {
			$this->sess_destroy ();
			return FALSE;
		}
		
		// Is the session current?
		if (($session ['last_activity'] + $this->sess_expiration) < $this->now) {
			$this->sess_destroy ();
			return FALSE;
		}
		
		// Does the IP Match?
		if ($this->sess_match_ip == TRUE and $session ['ip_address'] != $this->CI->input->ip_address ()) {
			$this->sess_destroy ();
			return FALSE;
		}
		
		// Does the User Agent Match?
		if ($this->sess_match_useragent == TRUE and trim ( $session ['user_agent'] ) != trim ( substr ( $this->CI->input->user_agent (), 0, 120 ) )) {
			$this->sess_destroy ();
			return FALSE;
		}
		
		// Is there a corresponding session in the DB?
		if ($this->sess_use_database === TRUE) {
			$this->CI->db->where ( 'session_id', $session ['session_id'] );
			
			if ($this->sess_match_ip == TRUE) {
				$this->CI->db->where ( 'ip_address', $session ['ip_address'] );
			}
			
			if ($this->sess_match_useragent == TRUE) {
				$this->CI->db->where ( 'user_agent', $session ['user_agent'] );
			}
			
			$query = $this->CI->db->get ( $this->sess_table_name );
			
			// No result?  Kill it!
			if ($query->num_rows () == 0) {
				$this->sess_destroy ();
				return FALSE;
			}
			
			// Is there custom data?  If so, add it to the main session array
			$row = $query->row ();
			if (isset ( $row->user_data ) and $row->user_data != '') {
				$custom_data = $this->_unserialize ( $row->user_data );
				
				if (is_array ( $custom_data )) {
					foreach ( $custom_data as $key => $val ) {
						$session [$key] = $val;
					}
				}
			}
		}
		
		// Session is valid!
		$this->userdata = $session;
		unset ( $session );
		
		return TRUE;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Write the session data
	 *
	 * @access	public
	 * @return	void
	 */
	function sess_write() {
		// Are we saving custom data to the DB?  If not, all we do is update the cookie
		if ($this->sess_use_database === FALSE) {
			$this->_set_cookie ();
			return;
		}
		
		// set the custom userdata, the session data we will set in a second
		$custom_userdata = $this->userdata;
		$cookie_userdata = array ();
		
		// Before continuing, we need to determine if there is any custom data to deal with.
		// Let's determine this by removing the default indexes to see if there's anything left in the array
		// and set the session data while we're at it
		foreach ( array ('session_id', 'ip_address', 'user_agent', 'last_activity' ) as $val ) {
			unset ( $custom_userdata [$val] );
			$cookie_userdata [$val] = $this->userdata [$val];
		}
		
		// Did we find any custom data?  If not, we turn the empty array into a string
		// since there's no reason to serialize and store an empty array in the DB
		if (count ( $custom_userdata ) === 0) {
			$custom_userdata = '';
		} else {
			// Serialize the custom data array so we can store it
			$custom_userdata = $this->_serialize ( $custom_userdata );
		}
		
		// Run the update query
		$this->CI->db->where ( 'session_id', $this->userdata ['session_id'] );
		$this->CI->db->update ( $this->sess_table_name, array ('last_activity' => $this->userdata ['last_activity'], 'user_data' => $custom_userdata ) );
		
		// Write the cookie.  Notice that we manually pass the cookie data array to the
		// _set_cookie() function. Normally that function will store $this->userdata, but
		// in this case that array contains custom data, which we do not want in the cookie.
		$this->_set_cookie ( $cookie_userdata );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Create a new session
	 *
	 * @access	public
	 * @return	void
	 */
	function sess_create() {
		$sessid = '';
		while ( strlen ( $sessid ) < 32 ) {
			$sessid .= mt_rand ( 0, mt_getrandmax () );
		}
		
		// To make the session ID even more secure we'll combine it with the user's IP
		$sessid .= $this->CI->input->ip_address ();
		
		$this->userdata = array ('session_id' => md5 ( uniqid ( $sessid, TRUE ) ), 'ip_address' => $this->CI->input->ip_address (), 'user_agent' => substr ( $this->CI->input->user_agent (), 0, 120 ), 'last_activity' => $this->now );
		
		// Save the data to the DB if needed
		if ($this->sess_use_database === TRUE) {
			$this->CI->db->query ( $this->CI->db->insert_string ( $this->sess_table_name, $this->userdata ) );
		}
		
		// Write the cookie
		$this->_set_cookie ();
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Update an existing session
	 *
	 * @access	public
	 * @return	void
	 */
	function sess_update() {
		// We only update the session every five minutes by default
		if (($this->userdata ['last_activity'] + $this->sess_time_to_update) >= $this->now) {
			return;
		}
		
		// Save the old session id so we know which record to
		// update in the database if we need it
		$old_sessid = $this->userdata ['session_id'];
		$new_sessid = '';
		while ( strlen ( $new_sessid ) < 32 ) {
			$new_sessid .= mt_rand ( 0, mt_getrandmax () );
		}
		
		// To make the session ID even more secure we'll combine it with the user's IP
		$new_sessid .= $this->CI->input->ip_address ();
		
		// Turn it into a hash
		$new_sessid = md5 ( uniqid ( $new_sessid, TRUE ) );
		
		// Update the session data in the session data array
		$this->userdata ['session_id'] = $new_sessid;
		$this->userdata ['last_activity'] = $this->now;
		
		// _set_cookie() will handle this for us if we aren't using database sessions
		// by pushing all userdata to the cookie.
		$cookie_data = NULL;
		
		// Update the session ID and last_activity field in the DB if needed
		if ($this->sess_use_database === TRUE) {
			// set cookie explicitly to only have our session data
			$cookie_data = array ();
			foreach ( array ('session_id', 'ip_address', 'user_agent', 'last_activity' ) as $val ) {
				$cookie_data [$val] = $this->userdata [$val];
			}
			
			$this->CI->db->query ( $this->CI->db->update_string ( $this->sess_table_name, array ('last_activity' => $this->now, 'session_id' => $new_sessid ), array ('session_id' => $old_sessid ) ) );
		}
		
		// Write the cookie
		$this->_set_cookie ( $cookie_data );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Destroy the current session
	 *
	 * @access	public
	 * @return	void
	 */
	function sess_destroy() {
		// Kill the session DB row
		if ($this->sess_use_database === TRUE and isset ( $this->userdata ['session_id'] )) {
			$this->CI->db->where ( 'session_id', $this->userdata ['session_id'] );
			$this->CI->db->delete ( $this->sess_table_name );
		}
		
		// Kill the cookie
		setcookie ( $this->sess_cookie_name, addslashes ( serialize ( array () ) ), ($this->now - 31500000), $this->cookie_path, $this->cookie_domain, 0 );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Fetch a specific item from the session array
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function userdata($item) {
		return (! isset ( $this->userdata [$item] )) ? FALSE : $this->userdata [$item];
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Fetch all session data
	 *
	 * @access	public
	 * @return	array
	 */
	function all_userdata() {
		return $this->userdata;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Add or change data in the "userdata" array
	 *
	 * @access	public
	 * @param	mixed
	 * @param	string
	 * @return	void
	 */
	function set_userdata($newdata = array(), $newval = '') {
		if (is_string ( $newdata )) {
			$newdata = array ($newdata => $newval );
		}
		
		if (count ( $newdata ) > 0) {
			foreach ( $newdata as $key => $val ) {
				$this->userdata [$key] = $val;
			}
		}
		
		$this->sess_write ();
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Delete a session variable from the "userdata" array
	 *
	 * @access	array
	 * @return	void
	 */
	function unset_userdata($newdata = array()) {
		if (is_string ( $newdata )) {
			$newdata = array ($newdata => '' );
		}
		
		if (count ( $newdata ) > 0) {
			foreach ( $newdata as $key => $val ) {
				unset ( $this->userdata [$key] );
			}
		}
		
		$this->sess_write ();
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Add or change flashdata, only available
	 * until the next request
	 *
	 * @access	public
	 * @param	mixed
	 * @param	string
	 * @return	void
	 */
	function set_flashdata($newdata = array(), $newval = '') {
		if (is_string ( $newdata )) {
			$newdata = array ($newdata => $newval );
		}
		
		if (count ( $newdata ) > 0) {
			foreach ( $newdata as $key => $val ) {
				$flashdata_key = $this->flashdata_key . ':new:' . $key;
				$this->set_userdata ( $flashdata_key, $val );
			}
		}
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Keeps existing flashdata available to next request.
	 *
	 * @access	public
	 * @param	string
	 * @return	void
	 */
	function keep_flashdata($key) {
		// 'old' flashdata gets removed.  Here we mark all
		// flashdata as 'new' to preserve it from _flashdata_sweep()
		// Note the function will return FALSE if the $key
		// provided cannot be found
		$old_flashdata_key = $this->flashdata_key . ':old:' . $key;
		$value = $this->userdata ( $old_flashdata_key );
		
		$new_flashdata_key = $this->flashdata_key . ':new:' . $key;
		$this->set_userdata ( $new_flashdata_key, $value );
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Fetch a specific flashdata item from the session array
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function flashdata($key) {
		$flashdata_key = $this->flashdata_key . ':old:' . $key;
		return $this->userdata ( $flashdata_key );
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Identifies flashdata as 'old' for removal
	 * when _flashdata_sweep() runs.
	 *
	 * @access	private
	 * @return	void
	 */
	function _flashdata_mark() {
		$userdata = $this->all_userdata ();
		foreach ( $userdata as $name => $value ) {
			$parts = explode ( ':new:', $name );
			if (is_array ( $parts ) && count ( $parts ) === 2) {
				$new_name = $this->flashdata_key . ':old:' . $parts [1];
				$this->set_userdata ( $new_name, $value );
				$this->unset_userdata ( $name );
			}
		}
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Removes all flashdata marked as 'old'
	 *
	 * @access	private
	 * @return	void
	 */
	
	function _flashdata_sweep() {
		$userdata = $this->all_userdata ();
		foreach ( $userdata as $key => $value ) {
			if (strpos ( $key, ':old:' )) {
				$this->unset_userdata ( $key );
			}
		}
	
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Get the "now" time
	 *
	 * @access	private
	 * @return	string
	 */
	function _get_time() {
		if (strtolower ( $this->time_reference ) == 'gmt') {
			$now = time ();
			$time = mktime ( gmdate ( "H", $now ), gmdate ( "i", $now ), gmdate ( "s", $now ), gmdate ( "m", $now ), gmdate ( "d", $now ), gmdate ( "Y", $now ) );
		} else {
			$time = time ();
		}
		
		return $time;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Write the session cookie
	 *
	 * @access	public
	 * @return	void
	 */
	function _set_cookie($cookie_data = NULL) {
		if (is_null ( $cookie_data )) {
			$cookie_data = $this->userdata;
		}
		
		// Serialize the userdata for the cookie
		$cookie_data = $this->_serialize ( $cookie_data );
		
		if ($this->sess_encrypt_cookie == TRUE) {
			$cookie_data = $this->CI->encrypt->encode ( $cookie_data );
		} else {
			// if encryption is not used, we provide an md5 hash to prevent userside tampering
			$cookie_data = $cookie_data . md5 ( $cookie_data . $this->encryption_key );
		}
		
		$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time ();
		
		// Set the cookie
		setcookie ( $this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain, $this->cookie_secure );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Serialize an array
	 *
	 * This function first converts any slashes found in the array to a temporary
	 * marker, so when it gets unserialized the slashes will be preserved
	 *
	 * @access	private
	 * @param	array
	 * @return	string
	 */
	function _serialize($data) {
		if (is_array ( $data )) {
			foreach ( $data as $key => $val ) {
				if (is_string ( $val )) {
					$data [$key] = str_replace ( '\\', '{{slash}}', $val );
				}
			}
		} else {
			if (is_string ( $data )) {
				$data = str_replace ( '\\', '{{slash}}', $data );
			}
		}
		
		return serialize ( $data );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Unserialize
	 *
	 * This function unserializes a data string, then converts any
	 * temporary slash markers back to actual slashes
	 *
	 * @access	private
	 * @param	array
	 * @return	string
	 */
	function _unserialize($data) {
		$data = @unserialize ( strip_slashes ( $data ) );
		
		if (is_array ( $data )) {
			foreach ( $data as $key => $val ) {
				if (is_string ( $val )) {
					$data [$key] = str_replace ( '{{slash}}', '\\', $val );
				}
			}
			
			return $data;
		}
		
		return (is_string ( $data )) ? str_replace ( '{{slash}}', '\\', $data ) : $data;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Garbage collection
	 *
	 * This deletes expired session rows from database
	 * if the probability percentage is met
	 *
	 * @access	public
	 * @return	void
	 */
	function _sess_gc() {
		if ($this->sess_use_database != TRUE) {
			return;
		}
		
		srand ( time () );
		if ((rand () % 100) < $this->gc_probability) {
			$expire = $this->now - $this->sess_expiration;
			
			$this->CI->db->where ( "last_activity < {$expire}" );
			$this->CI->db->delete ( $this->sess_table_name );
			
			log_message ( 'debug', 'Session garbage collection performed.' );
		}
	}

}
// END Session Class

/* End of file Session.php */
/* Location: ./system/libraries/Session.php */